Noel Jordan Jameson 1, Michael H. Azarian1, and Michael G. Pecht1
1CALCE, Center for Advanced Life Cycle Engineering, Department of Mechanical Engineering, University of Maryland, College Park, Maryland 20740, USA
Abstract:
Electromagnetic induction coils are widely
used in a variety of applications, many of them safetycritical.
The insulation around the wire in an electromagnetic
coil accounts for a significant portion of the failures in
solenoid-operated valves and in electric motors. This
paper presents a method of detecting the degradation of
insulation used in low-voltage applications by assessing
changes in impedance responses. The results indicate that
coil impedance, resolved into resistance and reactance,
evolves differently when the coil is subjected to different
loading conditions, which reflects insulation degradation
signatures due to different failure mechanisms. This
method can be used to assess the insulation life of an
electromagnetic coil, allowing replacement prior to the
formation of harmful shorts or critical coil opens.